Regarding Romans 1:20, I think he has it right:
At the same time, I don’t think these verses require us to conclude that creation itself indisputably proves God’s existence. If the world was such that a belief in God was the only logical conclusion, or the only logically consistent way of understanding the world, then God’s work is done from the beginning and he has no need to communicate any further. But this is not the story that the Bible tells. Instead, it indicates that God repeatedly reveals himself personally, culminating in his incarnation in Jesus. Yes, there are other purposes of the incarnation, but one of them is to enable knowledge of God. As Jesus himself says, “If you have known me, you will know my Father too. And from now on you do know him and have seen him” (John 14:7).